The present invention relates to a process for preparing multi-layered coated articles comprising a pigmented or colored base coat and a transparent or clear topcoat.
Color-plus-clear coating systems involving the application of a colored or pigmented base coat to a substrate followed by the application of a transparent or clear topcoat to the base coat have become conventional as original finishes for automobiles. The color-plus-clear systems have outstanding gloss ant distinctness of image.
Because many geographic areas encounter acidic precipitation, resistance to etching by atmospheric acrid precipitation ("acid etch resistance") is becoming an increasingly desirable property for coatings, particularly automotive original equipment coatings. Original equipment manufacturers are requiring that coating systems demonstrate acid etch resistance.
In addition to the requirement of acid etch resistance, original equipment coatings must also demonstrate mar and abrasion resistance; i.e., the appearance of coating must not be detrimentally affected when the coating is contacted with an abrasive material. Mar and abrasion resistance is a desirable property particularly due to the popularity of commercial car washes there brushes are often used to wash car bodies.
A number of commercial coating systems which demonstrate acid etch resistance do not provide adequate mar and abrasion resistance. Microparticulate materials such as silica, metal sulfides, and crosslinked styrene-butadiene have been added to these coating systems to improve mar resistance, but gloss and distinctness of image of the systems is adversely affected due to light scattering at the particle surfaces.
It would be desirable to provide a color-plus-clear composite coating system which avoids the marring problems of the prior art systems while maintaining excellent acid etch resistance and appearance properties.